I love the repaint pack idea. Great price point, this is about perfect for me to get a pack of zombies and a few good villain minis.

I think tying this into a free module is a great idea. If it could be done economically (say, for $2-$3 more) I would love to see these encounter packs actually bundled with a cheap set of map tiles and a single-page PF encounter similar to the now-defunct "complete encounter" metal mini sets. Having future encounter packs tie in to the latest adventure path / Gamemastery map / module subscription / etc would be sweet as well, and would be great marketing.